Press fitted sleeves



April 2, 1953 R. J. MATT ETAL. I 3,084,003

United States Patent O 3,084,0l3 PRESS FITTED SLEEVES Richard J. Matt,South Euclid, and Algirdas L. Nasvytis,

Cleveland, Ohio, assignors to Thompson Ramo Wouldridge Inc., Cleveland,Oho, a corporation of Ohio Filed Apr. 7, 1961, Ser. No. 101,479 2Claims. (Cl. 308-22) This invention relates to rockets, missiles andrelated air and space borne Vehicles, and is more particularly conceruedwith improved bearings, seals, liners and the like which may be employedover wide temperature ranges.

Aircraft and missile components have to operate over wide temperatureranges, and heretofore means for retaining bearings, seals, pistonliners, and the like which had limited applicability over these widetemperature ranges were employed.

Normally, standard procedure involves shrinking or press fitting aliner, having the desired wear properties or strength properties into alightweight housing. The weight problem is, it will be appreciated, ofgreat importance with respect to fiight Vehicles since each pound ofadditional weight sacrifices mileage. The importance of these featuresare easily recognized in other applications, such as in the automotivefield.

In press fitting such assem'blies, difficu-lties have heretofore beenencountered under Operating conditions as the assembly temperature risessince the press or shrink fit which exists at room temperature may belost at higher or lower temperatures. The lightweight housing, Willshrink down normally faster than the liners, and stresses will graduallyincrease in the lightweight housing to the point where they may reachthe yield point and permanently deform. Thus, when the unit returns to ahigher temperature or lower temperature, the initial press or Shrink fitis no longer present.

With the present invention, we substantially overcome the problems anddifiiculties of the prior art and provide press fitted liners or sleevesfor environments involving wide temperature ranges.

It is therefore an object of the present invention to provide pressfitted sleeves for environments involving wide temperature ranges.

It is another object of the present |invention to provide press fittedsleeves which will expand and contract due to temperature change overwide temperature limits without imposing undue stresses on the housingWith which employed.

Still `another object of the present invention is to provide pressfitted retaining members which do not impose st es-ses in the assemblieswith which they are employed to an extent suflicient to permanentlydeform the assembly.

Another object of the present invention is to provide an improved methodof press fitting retaining members in assemblies `in such a manner thatoperation of the assemblies |over wide temperature lranges does notafect the initial press or shrink fit of the retainin-g members.

These and other objects, features and advantages of the presentinvention will 'become lreadily apparent from a careful consideration ofthe following detailed description, when considered in conjunction withthe accompanying dr'awing .illustrating preferred embodiments of thepresent invention and Wherein `like referen numerals and charactersrefer to like and corresponding parts throughout the several views.

On the drawings:

FIGURE 1 is an enlarged fragmentary view vin cross section of a liner orsleeve constructed in accordance with the princ-iples of 'the presentinvention.

FIGURE 2 is an enlarged fragmentary view of an alternative embodiment ofthe liner or sleeve of FIG- URE l.

FIGU'RE 3 is -a .fur-thor embodiment of the present invention wherein aplurality of spaced keys are employed.

As shown on the drawin-gs:

Although the present invention has a variety of applications, one 'suchapplication appears in FIGURE 1 wherein a `lightweight housing 4 isprovided with a liner 5 having a smooth bore, generally indicated by thenumeral 6, and a splined outer surface 7 adj-acent the inner wall 8 'ofthe housing L3.

The liner '5 may be constructed of a `material heavier in Weight thanthe housing and the housing 4 may have a different ooefiicient ofthermal expansion than the sleeve or liner 5. 'The liner or sleeve 5 maybe employed as a cylinder liner in sleeve bearings or sleeve 'bearingsupports in piston engines.

When the material defining a hole or a plug expands or contracts due totemperature change, all ygrowth of the material occur-s along radiallines so that, in effect, there is no circumferential movement of aparticle or molecule on the surface of the material definin-g the holeor plug. Thus, growth always takes place radially inward or out- Ward.The realization of 'the application of this principle provides animportant feature of the present invention as next explained.

The outer periphery of the surface 7 of the liner 5 is provided with aplurality of projections or splines 9. The splines 9 eXtend into grooves10 formed in the housing 4 'to maintain the liner in fixed positionrelative to the housing 4. Thus, a male and female type Cooperation isprovided.

if the side walls 11 and 12 of the projection 9 are di- `vergentlytapered from the surface 7 of the liner and are radially aligned with orfollow the same radiai lines R from the center C or axis of the liner 5,as the cornplementary surfaces 13- and f14 of the housing 4- againstwhich the projections or splines are press or Shrink fitted, crushing ofthese complementary surfaces Will not occur due to temperature changeregardless of the differences in coeficient of expansion of the materialof construction of the housing 4 and projections 9, within predeterminedtemperature limits.

The diferences in the coelficients of expansion between the housing 4and spline 5 will have an effect on the diameter of the housing andsleeve 5 during a temperature change. To compensate for the differencesin the change in diameters, a clearance space 15 is provided between theouter peripheral edge 16 of each projection and the complementary bottomwall or surface 17 of the grooves 10. The outer peripheral edge 16 ofthe projection 9 is preferably shaped to the surface 17 and thus may bearcuate as shown in FIGURE l.

The clearance space '15 is of predetermined climension so that over thetotal temperature range, contact between the surface 16 and surface 17does not occur.

A similar effect is provided between the Sections between theprojections A clearance 18 of predetermined dimension is maintainedbetween the inner surface 3 of the housing 4 and outer surface 7 of theliner 5. Thus contact between the liner and the housing is limited tothe side walls of the spline or projcctions 9 over the predeterminedtemperature range in which the asseinbly is required to operate.

The overall effect of a liner constructed in accordance with the presentinvention is that the bore diameter D of the liner is affected only bythe coefficient of expansion of the liner itself and is not afected byshrinkage or enlargement of the housing 4. Thus stresses are not appliedto the liner by the housing and its coetiicient of expansion remains thesame. Similarly, the liner does not apply stresses to the housing andits coefficient of expansion remains the same.

ln FiGURE 2 an alternative ernbodiment of FIGURE 1 is disclosed whereinthe side walls of the spline 9' are parallel. These side walls'areindicated by the numerals 20 and 21. In this embodiment, wherein thesplines 9' are relatively thin in cross section, the effect of thermalexpansion is thus relatively small on the cross section that is notfollowing expansion along radial lines. In this embodiment the space 15between the surfaces 17 and 16 is maintained as well as the spaeingbetween surfaces 7 and 8. The manufacturing errors in producing thesethin cross section projections 9' will be compensated for in the smallerwidth thereof and, therefore, in principle, these projections 9' followthe radial line expansion and contraction concept but any deviationthereof is compensated for by the small cross section of the spline 9',when press fitted in the groove 110.

In FIGURE 3 an alternative embodiment of the present nvention isdisclosed wherein the splnes are independent retaining members 25 seatedin grooves 2x5 formed in the liner 27. With this embodiment theretaining members 25 have opposed divergingly tapered sides 29 Vwhichare press fitted into the liner groove 26 and into the groove defined bythe housing 4. The predetermined space is provided as Well as the space18. This embodiment finds applicability where the housing has a long uselife and the temperature ranges to which it may be exposed in differentapplications may vary. With the separate retaining members and separatesleeves of different dimension, the spaces 15 and 18 may -be varied forthe different temperature range applications.

The principles of the present nvention may also be employed inapplications wherein a pin is fitted into a hole, such as a key and'slot (not shown) and a speeified clearance must be maintainedtherebetween over the entire Operating temperature range.

Although various minor modifications of the present nvention will'become readily apparent to those skilled in the art, it should beunderstood that we wish to ernbody within the scope of the patentwarranted hereon all such embodiments as reasonably and properly comewithin the scope of our appended claims.

We clam as our nvention:

1. An assembly adapted for use as a bearing housing and the like over awide Operating temperature range comprising: a housing having a linerreceiving bore, a plurality of spaced grooves in .the bore definingsurface of the housing and said housing grooves having parallel sides, aliner in the bore, and spaced thin cross section projections carried bythe liner extending beyond the outer surface of the liner, each of saidprojections having in cross section parallel side walls sized for pressfitted engagement With complementary side walls of the grooves formed inthe housing, the projections and outside diameter of the liner being ofpredetermined dimension relative to the housing grooves and to thehousing respectively to provide spaces therebetween of a dimensionsufficient to permit thermal expansion and contracrion of the liner andhousing over a predetermined temperature range.

2. A member adapted for use as a press fitted liner for 'bearinghousings and the like over a wide operating temperature rangecomprising: a bored liner sized for insertion in a housing, a pluralityof grooves formed in the outer surface of the liner and a plurality ofgrooves formed in the inner surface of the housing, the housing groovesand the liner grooves being radially aligned, and a plurality ofseparate retaining members seated in said grooves formed in the outersurface of the liner having the base of the retaining members engagingthe base of the liner groove, and said retaining members projecting'beyond the outer surface of the liner, each of said retaining membershaving side walls divergingly tapered in cross section to the outerperipheral edge of the retaining member along lines radially algned withthe axis of the liner, said side walls being sized for press fittedengagement with complementary side walls of a groove formed in thehousing, the retaining members and the outside diameter of the linerbeing of'predetermined dimension relative to the grooves of the housingand to the housing respectively to provide spaces therebctween of adimension to permit thermal expansion and contraction of the member andvhousing over a predetermined temperature range.

References Cited in the file of this patent UNITED STATES PATENTS

1. AN ASSEMBLY ADAPTED FOR USE AS A BEARING HOUSING AND THE LIKE OVER AWIDE OPERATING TEMPERATURE RANGE COMPRISING: A HOUSING HAVING A LINERRECEIVING BORE, A PLURALITY OF SPACED GROOVES IN THE BORE DEFININGSURFACE OF THE HOUSING AND SAID HOUSING GROOVES HAVING PARALLEL SIDES, ALINER IN THE BORE, AND SPACED THIN CROSS SECTION PROJECTIONS CARRIED BYTHE LINER EXTENDING BEYOND THE OUTER SURFACE OF THE LINER, EACH OF SAIDPROJECTIONS HAVING IN CROSS SECTION PARALLEL SIDE WALLS SIZED FOR PRESSFITTED ENGAGEMENT WITH COMPLEMENTARY SIDE WALLS OF THE GROOVES FORMED INTHE HOUSING, THE PROJECTIONS AND OUTSIDE DIAMETER OF THE LINER BEING OFPREDETERMINED DIMENSION RELATIVE TO THE HOUSING GROOVES AND TO THEHOUSING RESPECTIVELY TO PROVIDE SPACES THEREBETWEEN OF A DIMENSIONSUFFICIENT TO PERMIT THERMAL EXPANSION AND CONTRACTION OF THE LINER ANDHOUSING OVER A PREDETERMINED TEMPERATURE RANGE.